Brand new to the forum and the site, discovered it today actually at work :)
Looking to get some experience with building a PC and putting a kick ass (my standards) rig together.

So let me start off with the list:

1. What YOUR PC will be used for. That means what types of tasks you'll be performing.
This will range from software dev. to gaming to minor video editing

2. What YOURbudget is. A price range is acceptable as long as it's not more than a 20% spread
1500 20% spread.
3. What countryYOU will be buying YOUR parts from.
I live in Vancouver, Canada
4. IF YOU have a brand preference. That means, are you an Intel-Fanboy,ATI (XFX) -Fanboy, Asus- Fanboy
I'm also a Samsung fan but it wouldn't really apply here.
5. If YOU intend on using any of YOURcurrent parts, and if so, what those parts are.
I will reuse my DVD burner that I had upgraded, but that's about it.

6. IF YOU have searched and/or read similar threads.
Looked at various I7 threads on here and elsewhere.

7. IF YOU plan on overclocking or run the system at default speeds.
I will overclock a bit, only to do it and learn how. Never done it before though.

8. WHEN do you plan to build it?
Start getting the parts and have it done in the next 3 or 4 weeks.

Since I live in Vancouver, it makes sense to go to NCIX for most of this stuff. I'm not sure how good their price matching is because I found this website to point to Newegg.ca and other sites with almost always cheaper prices.
RIG:

I decided against the 5850 because of the overpricing. Is it really worth it?

What I am unsure about is the Heat sink. Is it really necessary?
I'm also unsure about the PSU I picked out. I want to get a PSU that will last for a long time and can be reused in another build down the road.

5850 is worth it. It's not *that* overpriced, and if you game on a reasonably high resolution monitor (1080p or higher), you'll definitely not regret stepping up that 5770 to a 5850. Actually if budget permits, I'd say go for a 5870 even.

Another motherboard choice could be the Gigabyte X58A-UD7.

For RAM, this G.SKILL 6GB DDR3 1333 has lower latency and tighter timings. I have no idea why Newegg ran out of stock, because I checked just two days ago and they still had it. Maybe you can find it at NCIX.

If you are going to do any overclocking on an i7, you definitely want to replace the stock HSF with something better. That Noctua isn't bad, but you could also get the Prolimatech Megahalems, or the Noctua NH-D14. The NH-D14 is currently the air champion on LGA 1366, but it may be too expensive. The Corsair Hydro H50 is also a good choice for budget liquid cooling.

That PSU is great, and for your current setup, it'll be more than enough. However if you plan to do CrossFire in the future with significant CPU OC, you might want to consider the 750W version for only $20 more. Although for 2x 5770 CrossFire, the 650W PSU should be enough. If you do end up getting a 5850 or 5870, and plan to CrossFire in the future, consider the 750W step up.

First, how long do you plan to use this computer? Do you want it to last 5-6 years? If so, you're going about it the wrong way. If you want 2 years this should be a good rig, probably 4 if you're willing to do incremental upgrades.

My recommendation with the video card:

Are you using desktop discrete graphics right now that you might be able to cross over to the new system? I suggest it only because GPU prices right now are very high, and in a few months when Fermi releases there's going to be more options and (more importantly) a substantial ATI price drop is expected. If whatever graphics you have can be used on the new system and aren't dramatically weak (i.e. you can stand using them until Fermi) keep them, save a bit now, and spend it when there's a good price drop and you can get a 5850 for $50-70 cheaper.

Also, since video-editing seems to be less important than gaming, I might recommend going with LGA 1156. It doesn't look like you have much intention of using more than 2 video cards (based on your PSU) and since you probably won't need LGA 1366's processing power (not that it's very much better right now anyway) you can save a lot of money by getting a good LGA 1156 board and an i5 750 or i7 860. The difference is marginal (next-to-none if you're gaming) and it's substantially cheaper. Spend the extra money on some games (or whatever the hell you want).

Finally, since you're not planning on doing anything crazy in the OC department, you might drop to a Hyper 212 Plus cooler, just to save some cash. It does REALLY well for the price, especially if you're not going above 3.8GHz or so (on a 920). Really all you're paying for on the Noctua are the 2 $25 fans. If you don't need the quietness of the P12s, it's not necessary.

__________________
"If dancing is sure to result in failure then you must dance anyway."
Lo Mein said that, and I think he knows a little more about dancing than I do pal, because he invented it! Then he perfected it so that no man could best him in the club of honor.
Then he used his prize money to buy two of every whore on Earth. Then he herded them all onto a boat, then they all beat the crap out of every single one of him.

I will probably go for either the H50 or the Noctua NH-D14. I will also probably step up to the 750 W as the added cost is minimal.
Will get the G.Skill.

As for the motherboard, the Gigabyte UD7 looks pretty craze. What's the main difference between the UD5 and UD7? And the biggest difference between UD7 and the Asus board other than the 3 way SLI/cross? I will want to use the motherboard as long as possible.

Raserei,
I think your right about the graphics card. I have a couple of AGP's, one maybe 2 years old, but from what I remember you can't use AGP cards on PCI motherboards at all. stupid decision to buy that card, played thief and that's about it. I'm not in a huge hurry, so maybe I should wait till march to even get the card at all, or buy even a cheaper card than the 5770.
I personally don't think any machine can last for 6 years when gaming. 6 years is a really long time, and it is impossible to predict the technology in 6 years, 1 thing is for sure, it will be incomparable to anything you can get now. I think planning for around 4-5 years with incremental upgrades is the best you can do, making sure you never get the "hottest" card. I got my current rig around 4-5 years ago, and did incremental upgrades (but could only go so far as mobo was AGP, I was young and stupid, now mostly just stupid). The reason is simply this:
GPU's are the most complex and powerful chips on the planet. My proff. was telling us about a team that was using GPU's for their weather prediction algorithms, their problem was that their algorithms took so long, the weather that they were supposed to predict would have already happened when the algorithm was done! What's driving GPU's? Gaming! GPU's are driving overall processing power, so they will always be changing in dramatic fashion.
1366 socket:
It seems more reasonable to get the latest socket for upgrade-ability reasons. How does getting the 1156 extend usability to 5-6 years? it's the older socket? I don't mean to challenge your advice, but I just don't understand.
I know that the difference between the 1156 and 1336 is minimal now, but I heard 8 cores will come out on 1366 in the future and not on 1156. I could be very wrong.

Also I don't want to cut my own leg and limit myself in terms of overclocking. I can afford the extra cash for better cooling just in case. I may also want more than 2 cards down the road, you never know!

Of those two coolers, I'd say get the D14. Honestly, calling the H50 watercooling is practically a disgrace to the practice, since it won't even beat some high-end air coolers. That said, most i7 chips crap out before 4.0GHz or so, and you can cool an i7 running that hot with a Hyper 212 Plus (though a D14 will be better). It's my opinion, though, that beyond the Hyper 212 Plus, the gains aren't really worth it until you can do a custom WC loop. With the voltage you'll be adding to get it beyond 4.0, the difference between a Hyper 212 Plus and a D14 aren't really going to get you anywhere. Also, if you do go with a D14, I suggest replacing the fans with 2 or 3 high-speed fans. It comes with great fans, but they don't move a lot of air.

Well, if all you've got are AGP cards doesn't look like you've got much of a choice, does it. If you can hold out until Fermi you'll be able to get a significantly better GPU for the same price.

As for 1156 vs 1366, your logic is sound. If you can afford the 1366 you might as well go for it for the future upgradability, especially if you're keeping the platform for 4-5 years.
Side note - that's a good length of time for keeping a core computer IMO. As long as you're willing to do a few GPU upgrades (and maybe a CPU) along the way the computer should last you that long.

As for a 1000W, meh, odds are you'll want a new PSU before you max that out (unless you're running 3-4 cards). I'd rather get a good 850W over a cheaper 1000W. Regardless, the 750TX or something similar should be more than enough for i7 and 2 5770s or 5850s. The newer 40nm cards use surprisingly little power.

Also, small correction; 1156 is actually a bit newer than 1366, but it's lower end. On the other hand, motherboards are a lot cheaper and they tend to get better support for newer technology (SATA 6 and USB 3) at the moment. Should even out soon enough.

__________________
"If dancing is sure to result in failure then you must dance anyway."
Lo Mein said that, and I think he knows a little more about dancing than I do pal, because he invented it! Then he perfected it so that no man could best him in the club of honor.
Then he used his prize money to buy two of every whore on Earth. Then he herded them all onto a boat, then they all beat the crap out of every single one of him.

Only difference between UD5 and UD7 are the north bridge cooling design - UD7 has an added large Silent Heat Pipe heatsink that occupies an expansion slot, UD5 just has the regular dual-heatpipe heatsink. I have the UD5 and it keeps my northbridge very cool, so I don't see the need to step up and get the UD7. The underlying board is identical.

I was in the same situation as you. If your not in too much of a hurry, you can find pretty good deals on this site, redflagdeals, Ebay etc...
I picked up a Brand New Sealed i7 920 D0 off kijiji for $250.00 + $20.00 shipping. That's a pretty good deal.
If you drive to the states, you can go to Microcenter in Boston. They have great open box prices. You may also want to check on Ebay NCIX outlet. They have very good open box deals with full warranty.
I picked up a Gigabyte EX58-UD5 for $210.00.